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Tom,
Makes sense, providing of course, that the heat source is
economical.
We have heated material prior to densification, but never to
the temperatures you suggest. I would guess the determining factors would be the
cost of the required heat and the transportation costs saved.
Would be glad to help develop some data.
Jim Dunham
Environmental Engineering Corp.
Kansas City, MO
816-452-6663
Dear All:
The widespread use of
biomass energy depends on a convenient supply of large
quantities of
biomass. Densification can help with this because it makes
many
kinds of waste into a very acceptable - desirable fuel. Gasifiers,
pellet stoves and woodgas stoves all benefit from using densified wood.
In 1979 we found in static tests on pelletizing that
Preheating reduced the needed pressure required by a factor of 2
Energy for densification was also reduced by a factor of 2 at 225 C
The energy content of the resulting pellets rose from 19.3 kJ/g at
room
temperature to 21.4 kJ/g at 225 C (23.0) at 250 C)
["Biomass Densification Energy Requirements", T. Reed, G. Trezek,
and L.
Diaz, in Thermal Conversion of Solid Wastes", J. L. Jones and S. B.
Radding,
ACS Symposium Series 130, Was. D.C., 1980. I still have the
pellets in my
"museum".]
In a recent article the Asian
Institute of Technology found significantly
reduced energy and die wear
from preheating biomass before pelletizing.
~~~~~
Now (1982 actually) comes torrefied wood, (wood roasted at 200-250 C
to
remove primarily water and CO2, leaving a higher energy content and,
lower
mass for shipping).
The next obvious step would be to
combine the two processes, Torrefying the
wood and then immediately
densifying it while it is hot and weak, thus
compounding the benefits of
both processes.
If anyone is interested in pursuing this I
would be happy to cooperate with
them.
In a message dated
12/19/00 8:41:32 AM Mountain Standard Time,
heat-win@cwcom.net writes:
Dear All,
In connection with greenhouses you will
find much interesting
information re. charcoal and torrefied wood at .
If for example tomatoes are being grown, the vines left over can be
torrefied and used to fuel the greenhouse heating. If there aren't
enough, then other renewable fuels such as wood pellets can be used.
Regarding the lime kilns, have a look at , in
particular the
RofireTM link you will find there. Cement kilns are now
being heated
using RofireTM pellets made from the un-reusable fibres,
plastic, etc,
left over from the recycling of paper.
Whatever else you do to
counter the natural gas and oil price crises,
please go out and plant
more trees!
Regards,
Thomas J Stubbing
John
Flottvik wrote:
Thomas B. Reed
President - The
Biomass Energy Foundation
1810 Smith Rd., Golden, CO 80401
Reedtb2@cs.com; 303 278 0558
Research Director,
The
Community Power Corporation,
8420 S. Continental Divide Rd.
Littleton,
CO 80127
303 933 3135
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